pgstmt: add Not cond

pgstmt/cond.go

@@ -28,6 +28,7 @@ type Cond interface {
 	IsNull(field string)
 	IsNotNull(field string)
 	Raw(sql string)
+	Not(f func(b Cond))
 	And(f func(b Cond))
 	Or(f func(b Cond))
 	Mode() CondMode
@@ -188,6 +189,17 @@ func (st *cond) Raw(sql string) {
 	st.ops.push(sql)
 }
 
+func (st *cond) Not(b func(b Cond)) {
+	var x cond
+	x.ops.sep = " and "
+	x.nested = true
+	b(&x)
+
+	if !x.empty() {
+		st.ops.push(withParen(" ", "not", &x))
+	}
+}
+
 func (st *cond) And(f func(b Cond)) {
 	var x cond
 	x.ops.sep = " and "

pgstmt/select_test.go

@@ -483,6 +483,25 @@ func TestSelect(t *testing.T) {
 			`,
 			nil,
 		},
+		{
+			"select where not",
+			pgstmt.Select(func(b pgstmt.SelectStatement) {
+				b.Columns("*")
+				b.From("table1")
+				b.Where(func(b pgstmt.Cond) {
+					b.Eq("id", 1)
+					b.Not(func(b pgstmt.Cond) {
+						b.Op("tags", "@>", pq.Array([]string{"a", "b"}))
+					})
+				})
+			}),
+			`
+				select *
+				from table1
+				where (id = $1 and (not (tags @> $2)))
+			`,
+			[]any{1, pq.Array([]string{"a", "b"})},
+		},
 	}
 
 	for _, tC := range cases {